/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.naming.java;

import java.util.Hashtable;

import javax.naming.Context;
import javax.naming.Name;
import javax.naming.NamingException;
import javax.naming.spi.InitialContextFactory;
import javax.naming.spi.ObjectFactory;

import org.apache.naming.ContextBindings;
import org.apache.naming.NamingContext;
import org.apache.naming.SelectorContext;

/**
 * Context factory for the "java:" namespace.
 * <p>
 * <b>Important note</b> : This factory MUST be associated with the "java" URL
 * prefix, which can be done by either :
 * <ul>
 * <li>Adding a java.naming.factory.url.pkgs=org.apache.catalina.util.naming
 * property to the JNDI properties file</li>
 * <li>Setting an environment variable named Context.URL_PKG_PREFIXES with its
 * value including the org.apache.catalina.util.naming package name. More detail
 * about this can be found in the JNDI documentation :
 * {@link javax.naming.spi.NamingManager#getURLContext(java.lang.String, java.util.Hashtable)}.</li>
 * </ul>
 * 
 * @author Remy Maucherat
 * @version $Revision: 467222 $ $Date: 2006-10-24 11:17:11 +0800 (星期二, 24 十月
 *          2006) $
 */

public class javaURLContextFactory implements ObjectFactory,
		InitialContextFactory {

	// ----------------------------------------------------------- Constructors

	// -------------------------------------------------------------- Constants

	public static final String MAIN = "initialContext";

	// ----------------------------------------------------- Instance Variables

	/**
	 * Initial context.
	 */
	protected static Context initialContext = null;

	// --------------------------------------------------------- Public Methods

	// -------------------------------------------------- ObjectFactory Methods

	/**
	 * Crete a new Context's instance.
	 */
	public Object getObjectInstance(Object obj, Name name, Context nameCtx,
			Hashtable environment) throws NamingException {
		if ((ContextBindings.isThreadBound())
				|| (ContextBindings.isClassLoaderBound())) {
			return new SelectorContext(environment);
		} else {
			return null;
		}
	}

	/**
	 * Get a new (writable) initial context.
	 */
	public Context getInitialContext(Hashtable environment)
			throws NamingException {
		if (ContextBindings.isThreadBound()
				|| (ContextBindings.isClassLoaderBound())) {
			// Redirect the request to the bound initial context
			return new SelectorContext(environment, true);
		} else {
			// If the thread is not bound, return a shared writable context
			if (initialContext == null)
				initialContext = new NamingContext(environment, MAIN);
			return initialContext;
		}
	}

}
